smegw01: Fix fallback to altbootcmd

The bootcmd/altbootcmd mechanism is not invoked for bootmenus.
Manually compare bootcount and bootlimit to implement fallback on all
codepaths.

Signed-off-by: Eduard Strehlau <eduard@lionizers.com>
Signed-off-by: Fabio Estevam <festevam@denx.de>